We did not confirm the report that a new serum alkaline phosphatase occurs as the dominant isozyme in lymphoproliferative diseases and our work shows that it is most unlikely that this isozyme exists. We were also unable to confirm the existence of a unique inhibitor of normal alkaline phosphatase in infectious mononucleosis serum and again it is unlikely that this inhibitor exists. We have demonstrated the existence of muscarinic cholinergic binding sites in neutrophils by the direct binding of labeled quinuclidinyl benzylate and have shown that this muscarinic antagonist prevents the augmented lysosomal release stimulated by carbamyl choline. There are a large number, on the order of ten to the 4th power, receptors per cell. We are investigating the nature of these receptors in normal neutrophils and those in chronic granulocytic leukemia.